Nelson h



@anni attire.

watson4 n. Bancone, or -NEWYORIL .N Y

` Letters Patent No. 105,626, dated-July 26, 1870; 'a-atedated July 19, 1870.

The Schedule referredf-tojin theseLetters Patent and making pari: ofthe same.4

tity ofwater or otherliqud isintrodilced, the air therein being whollyor partially exhausted, leavingmore or less of a vacuum or avacuous space wit-hin the-tubes above the waterwhich they contain. The tubes have their upper ends inserted ina vessel containing water, and their lower ends placed oyer a tire, like thev tubes I in that `class of boilers known as drop-tube steam boilers. The heat acts on the lower ends of the tubes,i

andconverts the water they contain into steam, which fills the vacuumspace above and transmits its heat by condensation to the water surrounding their upper ends, converting it into steam. Butin order that my invention may be fully understood, I shall now proceed l more particularly to descrihethe manner of performing the same, andfor thatpurpose shallrefer to the c several igures `in the accompanying drawing, the samefletters of` reference vindicating corresponding partsin all'the figures.

` Figure 1 is a side view of a single vacuum tube,

.apoition of the side at each end being removed to show thc waterland the vacuous space above it with-l in the tube.`

Figure 2 is a side elevation of a series of evaporators, A A, eachfcontaininga nnmberof vacuum-tubes,

a, and connected 'with `a water-reservoir, B, placed above, the whole-being set in a furnace.

t l Figureis a vertical section taken inthe line a z,

fig. 2, through the center of` a pair of evaporator-s, A A, showing upon an enlarged fscale the arrangement of the vacuum-tubes a a and the Ysteam and water- `pipes connecting the-evaporators with the reservoir B.

Fignret is a` transverse `section of a single evaporator,`A,-'taken in fthe line a: fc, fig. 3, showinghow the racuum-tubes a a, are arranged in the evaporator.'

f The vacuumtube aismade of copper oriron tubing; for ordinary purposes the-tubeis about eighteen inches longandthree-eighths ofuan inch in linside diameter. BothV ends of the tube are hermetically closed by brazing or welding, afterwhicha small hole is'drilled into one end; the tube is then moderately heated torarefy the air in its interior, and, while the tube is hot, it is plunged into water, -which rushes into the small hole and partly ills the tubewith water. The tube is then againheated until steam is generated and the 'air within is' expelled, when the-hole in the end of the tube is promptly plugged with ametal pin, b, fig. 1 ;"the pin is driven or screwed in tight and brazed' vto close the hole,l'iermetically. The tube will then contain a small quantityotl Water occupying a' part ofthe chamber, andl the rest of the space will be a partial vacuum,

that is to say, will be a space containing no xed gas.

And, if the tube has had the air `properly exhausted, and contain a sucient quantity of water, it will ring. as if the liquid were a piece of metal, when it is helil vertically and jerked up and down, so that the-water shall fall suddenlyfrom the uppery to the lower end.

The metallic sound thus produced by the water in a vacuum is the practical test of the perfect constrnc` tion ofthe tube, showing that it contains the neces sary quantity of water, and that the airhas been properly exhausted from it.

The quantity of water is not fixed, but, as a rule,

thc tube should containenough to ll the'vacuous.

space withstcam, while' a portionofthe water still remains at the lower end of the tube, whatever may be the temperature `to whichit is exposedl 4 On the upper end of the tube, in Iwhich isfthe' pin l, is out a screw-thread, to screw the tube through the bot-tom of the evaporator A, until its endreaches nearly to the top on the inside. The evaporator Ais a cylindrical cast-iron or coder-vessel, usually made about six inches `long and' .tive inches in diameter.V The nuinbcrof tubes 'in an evaporator will vary as required. i y

4The evaporators'AA may be arranged in pairs, as seen in iig. 3, transversely under a water-reservoir, B, which is an iron or-copper cylinder of any desired dimcnsions;

` 'lhey are secured to the reservoir by necks or nipples c c, which maybe madeV of malleablecast-iron, and are screwed into the top of the evaporator Aand through the bottom 'of the reservoir B.

A pipe or nozzle, d, is screwed into the end of the nipple c within the reservoir B, and is long enough for the end to project above the ,Water level and discharge steam into the steam space in the reservoir.

' A feed-pipe,e, passesv downl through the nipple o,

reaching nearly to the bottom of theevaporatonA it opens through the lower end of the nozzled into the reservoir B.

'The reservoir B and the evaporators AA are set in a furnace, as shown in tig. 2, with 1a portion :of 'the vacuumtubes a a projecting into the tire-box, while others occupy the due. evaporators A A with water from the reservoir B;

The water within the tubes is converted into steam, which fills the vacuum-chambers within them, and, whatever may he the temperature to which the lower' ends of the tubes are exposed, the heat will be transmitted to the water within the evaporator A by the steam with perfect safety to the tubes; -they will not be injured bythe hottest tire, so long as the u'pperends of the tubes are partially surrounded with water.

lhe steam within the vacuum-tubes isV condensed at their upper ends, which are in contact with the water in the evaporators, and transmits the heat as rapidly as it can be absorbed by the lower ends of the tubes in the tire.

The heat'thus transmitted by the steamin the vacnum tubes a a' to the water in the evaporator A converts it into steam, which escapes through the nipple c and the nozzle d into the steam space of the water reservoir. B.

The `pressure of the steam is greater within the evaporator A, where evaporation takes place, than in the reservoir B, and the water is .kept down in the evaporator to the level due to that excess of pressure; hence, the water cannot lise from the evaporator through the nipple c to the interior of the nozzle d after steam has been raised and while the generator continues in operation. The steam thus escapes from the evaporating surfaces directly through the nozzle d into the steam-space of the water-reservoir B without passing through Water. The steam, consequently, is dry, or true steam, and, in this respect, ditfers from the steam made in ordinary boilers, which passes from the evaporating surfaces through the water hefore it can escape into the steamchamber.

The steam within the vacuum tubes a a parts with its heat to the water within t-he evaporator A, as rapidly as it is absorbed from the lire, because its condensation is not impeded or obstructed; for when condensation of steam takesV place in a'vacuum, nothing intervenes between the steam and the condensing surface of the metal.

The'fe'ed-pipe 'e supplies the rlhe temperature of 'the evaporating surfaces ofthe tubes will thus always be maintained, under the action of' the mostintense tire, atthat pointwhch is the most effective in generating steam, that is to say, at that degree just below the point at which water, in contact with metal, assumes the spherodal condition hence maximum results areattained in my improved steamgenerator.

It will be observed that the vacuum-tubes, being placed in a vertical position, present dre-surfaces at right angles to the current of the products of combustion, and hence'the heat is most effectively applied, and may be wholly utilized before it escapes.

`The evaporator A,`with its group of vacuum-tubes a a, constitute 'a unit, and it is only necessary to multiply units for steam-.generators of any required capacity.

Having .thus described the nature of my'invention, and the manner of performing the same, I wish it to be understood that I do not limit myself to the precise details ot' construction and arrangement hereinbefore described with reference to the accompanying drawing, as these may be variously modified without departing from the principle and nature of my invention; but

Vhat I claim, and4 desire to be secured to .me by Letters' Patent, is-

1. A tube or chamber hermetically closed, containing water or other liquid, from over whichthe air, or

'a portion of it, has been exhausted, leaving more or less of a vacuum therein, constructed and operating substantially as and for the purpose herein specified.

2. The evaporator A, in combination with the vacuum tubes c a, constructed and operating substantially as described.

3. The combination of the evaporator A and the steam and water-reseryoir'B, constructed and operating substantially as herein described.v

. NELSON H. BARBOUR.

Witnesses:

O. MAGDANIEL, LEWIS CARR. 

